764
FXUS65 KBOU 240204
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
804 PM MDT Thu May 23 2024

.KEY MESSAGES...

- Gusty winds from 55 to 65 mph in and near the northern foothills
  through 2 am. Snow showers will end by midnight in the mountains

- Typical summertime pattern coming up this weekend with some
  scattered showers and storms across the high terrain.

- Spotty elevated fire weather across the plains this weekend, mainly
  with stronger winds, but fuels remain on the greener side.&&

.SHORT TERM /Through Friday/...
Issued at 225 PM MDT Thu May 23 2024

There is an upper low circulation over north central Wyoming at
this time. South and southwesterly winds are increasing a bit over
the Colorado northeast plains currently. Speeds over the plains
are gusting from 15 to 25 mph. Temperatures over the plains are in
the mid 70s to lower 80s F. Dew point temperatures are mostly in
the 20s F, with 50s F over the far northeast corner. There is
isolated convection over the mountains mainly in Grand, Jackson
and Larimer Counties. There are also some Cumulus clouds over the
far northeast corned along the dry line.

Models show a weak upper trough axis to push eastwards across the
CWA this evening.  This is followed by moderately strong westerly
flow aloft for the rest of tonight and all of Friday.  There is
downward synoptic scale energy in place for most of tonight and
Friday. Models are still showing a cold front to push southward
across the plains early this evening. There is very little CAPE over
the forecast area after 00Z this evening. Precipitable water proggs
are in the 0.2 to 0.5 inch range this evening, then 0.1 to 0.3 inch
overnight and Friday morning.  By Friday afternoon, they come up
into the 0.2 to 0.5 inch range again.  Will go with minimal pops
early this evening, mainly over the alpine areas.  On Friday, even
less pops in the mountains and nothing elsewhere; it is stable and
there is less heating than today. For temperatures, Friday`s highs
look 3-6 C cooler than today`s and that is after a chilly start to
the day.

&&

.UPDATE...
Issued at 755 PM MDT Thu May 23 2024

A cold front has blasted its way across the plains with wind gusts
in the 45-55 mph range. Meanwhile, subsidence associated with an
upper level low to the north, combined with increasing cross-
barrier flow was leading to very gusty winds in and near the
foohills from Boulder north to the WY border. A few gusts in the
60-65 mph range will be possible through 2 am or so before
slowly decreasing overnight.

Meanwhile, snow showers will continue in the mtns thru midnight
with an additional inch or so of accumulation in some areas. After
midnight drier air will move in with activity gradually ending.
Finally, may see some scattered front mainly over the Palmer
Divide late tonight into early Fri morning.

&&

.SHORT TERM /Through Friday/...
Issued at 225 PM MDT Thu May 23 2024

There is an upper low circulation over north central Wyoming at
this time. South and southwesterly winds are increasing a bit over
the Colorado northeast plains currently. Speeds over the plains
are gusting from 15 to 25 mph. Temperatures over the plains are in
the mid 70s to lower 80s F. Dew point temperatures are mostly in
the 20s F, with 50s F over the far northeast corner. There is
isolated convection over the mountains mainly in Grand, Jackson
and Larimer Counties. There are also some Cumulus clouds over the
far northeast corned along the dry line.

Models show a weak upper trough axis to push eastwards across the
CWA this evening.  This is followed by moderately strong westerly
flow aloft for the rest of tonight and all of Friday.  There is
downward synoptic scale energy in place for most of tonight and
Friday. Models are still showing a cold front to push southward
across the plains early this evening. There is very little CAPE over
the forecast area after 00Z this evening. Precipitable water proggs
are in the 0.2 to 0.5 inch range this evening, then 0.1 to 0.3 inch
overnight and Friday morning.  By Friday afternoon, they come up
into the 0.2 to 0.5 inch range again.  Will go with minimal pops
early this evening, mainly over the alpine areas.  On Friday, even
less pops in the mountains and nothing elsewhere; it is stable and
there is less heating than today. For temperatures, Friday`s highs
look 3-6 C cooler than today`s and that is after a chilly start to
the day.

&&

.LONG TERM /Friday night through Thursday/...
Issued at 224 PM MDT Thu May 23 2024

Saturday...This looks like the best chances, 70-80%, for scattered
showers and thunderstorms over the high terrain pushing off into the
foothills as shortwave troughing pushes through the region. Stronger
westerly winds are also likely, a 60% chance, of exceeding 45 MPH
above 8,000 feet. Any fire weather concerns should be brief and
spotty across the plains. Having driven across much of the plains
this week, the finer fuels/grasses, look pretty green.

Sunday...NBM is keeping better coverage of showers and storms across
the region, though lower chances than Saturday, 30-40%. Guidance is
however trying to dry us out a tad more in the wake of the passing
shortwave trough of low pressure with shortwave ridging trying to
kick in quicker. We did lower PoPs a tad but do keep the higher
terrain in the better coverage of showers and storms. Given the
tighter pressure gradient and jet streak to our north, winds will be
a little stronger than on Saturday as well. Right now the signal
shows a bit more widespread 30-45 MPH gusts during the afternoon
hours from the higher terrain spreading across the northern I-25
corridor and adjacent plains.

Memorial Day - Thursday...Temperatures begin to moderate back to
above seasonal averages throughout the period with most rain chances
confined to the higher elevations until sometime around mid-week
where we could see some low-level moisture sneak back in from the
southeast providing more showers across the region.

&&

.AVIATION /00Z TAFS through 00Z Friday/...
Issued at 524 PM MDT Thu May 23 2024

Front was already crossing the area with gusty north winds behind
it. Not sure what directions will occur after 01z as they could go
more NW or NE. Confidence in either scenario is low at best. After
03z winds may become more east and then SE after 05z, in one
scenario, or go from NW to WNW to SSW in the other scenario.  On
Fri, winds will be S or SSE by 12z and then SE by 19z. Otherwise
VFR conditions thru the period.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...RPK
SHORT TERM...RJK
LONG TERM....Heavener
AVIATION...RPK